1. Field of the Invention
The present invention relates to a lens barrel that has a bending optical element such as a prism or a mirror.
2. Description of the Related Art
This kind of conventional lens barrel is provided with a lens frame that can move within a range between a retracted position and a taking position in an optical axis direction while holding a lens, and a prism that bends an incident light flux passing through the lens in a direction crossing the optical axis to guide the light flux to an image pickup device. The prism is located at the back side of the lens frame in the optical axis direction to bend the incident light flux to the image pickup device when the lens frame is in the taking position. The prism moves to an escape position from the back side of the lens frame in order to keep storage space of the lens frame when the lens frame is in the retracted position (see Japanese Laid-Open Patent Publication (Kokai) No. 2007-226106 (JP 2007-226106A)).
Incidentally, when the lens is moved in the optical axis direction together with the lens frame, a driving force of a motor is transmitted to a cam barrel that is engaged to the lens frame via a first transmission mechanism. When the prism is moved within a range between the back side position of the lens frame and the escape position, the driving force of the motor is transmitted to the prism via a second transmission mechanism.
However, JP 2007-226106A discloses the configuration in which the first transmission mechanism that transmits the driving force of the motor to the cam barrel and the second transmission mechanism that transmits the driving force of the motor to the prism are mutually separated in a direction (a diameter direction of the cam barrel) that intersects an axis of the cam barrel when viewing in the axial direction of the cam barrel. Therefore, the area, which is occupied by the first and second transmission mechanisms when viewing in the axial direction of the cam barrel, becomes large, which prevents an image pickup apparatus from miniaturizing.